1. Field of the Invention
The present invention relates to a radiation-curable ink composition for inkjet recording, an inkjet recording method using the ink composition, and a printed matter obtained by using the ink composition.
2. Related Art
Inkjet recording enables to form an image with simple and inexpensive manner. Inkjet recording has excellent applicability to printing on a recording medium with an irregular surface shape since it performs ejection of an ink from a nozzle which does not contact with a recording medium.
Limited kinds of recording media and costs accompanied therewith have been concerned with respect to inkjet recording, that requires exclusive paper as the recording media. There have been many attempts to print on a transferred medium which is different from the exclusive paper by the inkjet recording.
Attention has been recently focused on a solventless inkjet recording method which includes forming an image using a radiation-curable inkjet recording ink, which is an ink which can be cured by being irradiated with radiant rays such as ultraviolet rays, by ink-jetting and then irradiating the image with radiant rays such as ultraviolet rays to cure the ink.
In general, as compared to a water-based ink which contains water as a diluent and a solvent-type ink which contains an organic solvent as the diluent, an inkjet recording method based on a radiation-curable ink has merits such as wider application range of base materials due to its ability to print on non-absorbable base materials such as glass, metal, or plastic base materials, superior rub resistance and solvent resistance of an image formed thereby, higher sensitivity, higher productivity, or smaller affection on the human body or the environment due to smell or the like because a volatile solvent is not contained therein. Therefore, application of the inkjet recording method using the radiation-curable ink in industrial fields has been expected.
A radical polymerizable ultraviolet curable (UV-curable) ink, which contains an acrylic composition as its main component, and a cationic polymerizable UV-curable ink are known as the ink for inkjet recording of the radiation-curable ink. Unlike the radical polymerizable UV-curable ink, the cationic polymerizable-UV-curable ink is unaffected by inhibitory effect by oxygen. Therefore, the cationic polymerizable-ultraviolet curable ink has merits of high sensitivity and excellent productivity.